1. ** Refer to atomic mass on Periodic Table!!! **

2. Review *** a.) 1 a.m.u. = 1/12 the mass of a ____________ atom b.) subscript = # of ____________. Eg. How many total atoms in calcium nitrate?

3. MOLES * In Chemistry, we count using moles.* 1 Mole = 6 x 10 23 atoms (particles). (1 mole = # of atoms present in 12g of C-12)

4. Mole vs. Dozen To understand “moles” better, we should compare 1 mole and 1 dozen. Q.1. How many apples are in 1 dozen? Q.2. How many atoms are in 1 mole? Q.3. Which has a greater mass, 1 dozen apples or 1 dozen grapes? Q.4. Which has a greater mass, 1 mole of sodium atoms or 1 mole of mercury atoms?

5. Many names, same concept! Mass of 1 Mole = “gram atomic mass”, “gram formula mass”, “molar mass”, “formula weight”, “gram molecular mass”.

6. Practice – Use Periodic Table Eg. 1.) 1 atom of H = 1 a.m.u. 1 mole of H = 1g. 2.) 1 atom of C = 12 a.m.u. 1 mole of C = 12g. 3.) 1 atom of Mg = _____________ 1 mole of Mg = _____________ 4.) 2 atoms of Mg (or, “Mg 2 ”) = _______________ 2 moles of Mg = ___________ 5.) 1 molecule of CO 2 = ____________ 1 mole of CO 2 = ______________

7. Atomic Mass Atomic mass – The sum total mass of all present atoms (in a.m.u.) ** Always give your answer as specific as the question suggests. **

8. Atomic Mass Eg. Give the atomic mass for all of the following to the nearest tenth... 1.) KCl 2.) Ca 3 N 2 3.) (NH 4 ) 2 S 4.) CCl 4

9. Gram formula mass Gram formula mass (gfm) (a.k.a. “molecular mass” or “formula mass”) the sum total mass using grams (g) instead of a.m.u. (gfm) always equals 1 mole (mol) of a compound **(gfm = 1 mole) *** Q.1. How many molecules are in 1 mole?

10. Practice Eg. Give a.) the total # of atoms and b.) the gram formula mass (gfm) for each of the following (round to whole #) 1.) NaCl 2.) F 2 3.) K 2 CO 3 4.) Al(OH) 3 5.) C 6 H 12 O 6

11. Hydrates Hydrates: –Ionic compound with water (H 2 O) attached. –Hydrate = crystals that contain water molecules. –Anhydrous = substance without water molecules.

12. Hydrates Q.1 What is the mass of 1 mole of H 2 O (the gfm of H 2 O)? Q.2 What is the gram formula mass (gfm) of 5 H 2 O?

13. Hydrates Give the gram formula mass (gfm) for each of the following Hydrates: 1.) CuSO 4 ∙ 5H 2 O “ ∙ ” = “+” 2.) NiSO 4 ∙ 6H 2 O 3.) MgCl 2 ∙ 2H 2 O

14. Mole-Mass Conversions Total mass (g) = (# of Moles) x (gfm)

15. Eg.1 What is the mass of 3 moles of H 2 SO 4 ? Total mass = (3 mol)(gfm of H 2 SO 4 ) =_____________ Eg.2 What is mass of.5 moles of copper(II) sulfate?

16. Eg.1 How many moles are there in 88g of CO 2 ? Step 1: find the gfm of CO 2 Step 2: solve the equation Eg.2 How many moles are there in 72g of CH 4

17. Practice Problems 1.) What is the mass of 2 moles of iron(II) nitrite? 2.) How many moles are in 46g H 2 SO 4 ? 3.) What is the mass of 0.5 mol carbon dioxide? 4.) How many moles are in 544g CaSO 4 ?

18. % Composition 1.) What is the % composition of oxygen in H 2 O? 2.) What is the % composition of hydrogen in H 2 O?

19. % Composition % Composition =

20. Eg.1 What is the % composition of Carbon in CO 2 ? Step 1: get the gfm of C (“part”) Step 2: get the gfm of CO 2 (“total”) Step 3: plug into equation and solve.

21. Eg.2 Find the % composition of C, H, and O in C 6 H 12 O 6.

22. Eg.3 What is the % composition of water in CuSO 4 ∙ 5H 2 O? Eg.4 What is the % water in NiSO 4 ∙ 6H 2 O? What is the % Ni?

23. The Element Song

24. Empirical vs. Molecular Formula Molecular FormulaEmpirical Formula C6H6C6H6 CH CO 2 C 6 H 12 O 6 CH 2 O C2H4C2H4 CH 2 C 6 H 12 O 11

25. Empirical Formula Empirical Formula - Q. How do we get the Empirical Formula from the Molecular Formula???

26. ** Fill in the Empirical Formula for each of the following: Molecular FormulaEmpirical Formula C2H2C2H2 C 4 H 10 C 5 H 10 C5H9C5H9 C3H9O3C3H9O3

27. Converting Empirical Formula  Molecular Formula: Steps: 1.Identify the mass of the molecular formula (given) 2.Calculate the gfm of Empirical formula. 3.Divide molecular mass (step 1) by empirical mass (step 2) and record answer. x = 4.Multiply subscripts of Empirical formula by the answer in step 3 to get the Molecular formula.

28. Eg.1: The molecular mass of a substance is 48 a.m.u. and its empirical formula is CH 4. What is the molecular formula of this substance?

29. Eg.2: What is the molecular formula of a substance with a molecular mass of 30g and an empirical formula of CH 3 ?

30. Eg.3: A substance has an empirical formula of CH 2 O and a molecular mass of 180g. What is the molecular formula of this substance?

31. Eg.4: A substance has an empirical formula of CO 2 and a molecular mass of 44g. What is the molecular formula of this substance?

32. Stoichiometry and Balancing Equations **Chemical Equations – used to represent chemical reactions. In all chemical rxns., 3 types of Conservation take place: 1.) Mass 2.) Energy (Kinetics) 3.) Charge (#e- lost = #e- gained (Redox.))

33. **Important... SymbolMeaning , , , and = “yield”; separates reactants from products

34. Stoichiometry ** Stoichiometry – branch of chemistry that deals with the amounts of substances that enters (reactants) and leaves (products) a chemical reaction. **

35. Stoichiometry Coefficients = # moles of a compound –Eg. 5 _BaCl 2 = 5 moles of BaCl 2 Subscripts = # moles of atoms (inside of a compound) –Eg. 3 _Al 2 S 3 = ____ moles of the compound Al 2 S 3, _____ moles of Aluminum atoms and ____ moles of Sulfur atoms.

36. Stoichiometry 1.) __ Na + __ O 2  __ Na 2 O SOC = 2.) __ Al + __ O 2  __ Al 2 O 3 SOC =

37. Stoichiometry 3.) carbon + oxygen  carbon dioxideSOC = **Remember “BrINClHOF”!!!** 4.) hydrogen + oxygen  water SOC =

38. Stoichiometry ___ AlCl 3 + ____AgNO 3  ____AgCl + ____Al(NO 3 ) 3 Link – Balancing Equations (timed) Link 2 – Balancing Equations Handout

39. Stoichiometry Rule: 1.) If you change any coefficient in a balanced equation, you MUST change them all. 2.) To change coefficients, you must either multiply or divide by a number.

40. Stoichiometry Eg.1: ___KClO 3  ____KCl + ____O 2 How many moles of Oxygen gas will be produced if you decompose 4 moles of KClO 3 ?

41. Stoichiometry Eg.2: ___Zn + ___CuCl  ___ZnCl 2 + ___Cu How many moles of CuCl were used if 10 moles of copper metal were produced?

42. Stoichiometry Eg.3: ___ AlCl 3 + ____AgNO 3  ____AgCl + ____Al(NO 3 ) 3 How many moles of aluminum chloride must you use in the above reaction to produce 1.5 moles of silver chloride?